Code 19: Intermittent 7X Signal: Notes

The ignition control module sends a reference signal to the PCM 7 times per crankshaft revolution to indicate crankshaft position and RPM so that the PCM can determine when to pulse the ignition coils and control ignition timing. A 5-volt reference is supplied to the PCM from terminal "G" of the ignition module. This 5-volt reference signal is monitored by the PCM. The ignition module pulls this signal low based upon 7X reference pulses. The seventh pulse is used for crankshaft position (sync) reference. Code 19 is set if the PCM misses at least 20 sync pulses within 4 minutes and 16 seconds.

1. Determines if PCM recognizes a problem. If Code 19 does not set, problem is intermittent.
2. When a resync occurs, engine will stumble. This step determines if component connections or circuit is faulty.
3. Operating non-engine related components may generate electromagnetic interference which may cause a resync.